This invention relates generally to welding equipment and, more particularly, to training devices for use in the instruction of electric arc welding.
Complex motor skills must be learned to master the art of electric arc welding. Such skills are dictated in large part by the nature of the welding process. For example, the tip of the welding rod, or electrode, must be maintained at a substantially constant, predetermined distance from the workpiece to maintain a suitable electric arc. The rod becomes stuck if it is allowed to contact the hot metal puddle, and the arc extinguishes if the rod is withdrawn too far from the workpiece. Thus, the distance from the tip of the rod to the workpiece must be kept within a narrow range. This distance must be maintained even as the welding rod is consumed and thereby progressively shortened. Thus, the trainee must learn to continuously feed the rod into the electric arc at a predetermined rate to compensate for consumption of the rod, and at the same time maintain the tip of the rod spaced from the workpiece by a predetermined distance. Further, the tip of the welding rod must be advanced across the workpiece at a predetermined, substantially constant speed to form a welded bead, or seam, of uniform consistency, strength and appearance. Moreover, in accordance with conventional welding practice, the rod must be moved in a rhythmic back-and-forth pattern as it is advanced across the workpiece. The actual shape of this pattern varies depending on the type of weld joint being formed. Finally, the welding rod must be held at a predetermined, substantially constant angle with respect to the surface of the workpiece, even as the rod is advanced across a workpiece of irregular shape.
A trainee must learn to execute all of the foregoing movements smoothly, simultaneously and without interruption. Further, the trainee must learn to apply the technique to workpieces of different shapes and orientations. All of this requires the development of complex motor skills that require a high level of eye-hand coordination.
Electric arc welding has traditionally been taught with the use of actual welding equipment, at considerable cost in time and supplies. This approach has not been altogether satisfactory, however, because the development of the requisite motor skills is actually hindered by the use of actual welding equipment, for several reasons. First, a trainee's vision is significantly impaired by the protective welding helmet that must be worn. In this regard, the protective lenses in the helmet are so dark that a trainee can only see what he is doing when the arc is on, yet much time is spent in the early stages of learning with the arc extinguished as the trainee learns how to handle the welding rod. For the same reason, it is difficult for an instructor to monitor a trainee's progress and provide instruction under actual welding conditions. Further, defects in a welded joint made by a trainee are not always immediately apparent. The discovery of such defects may require resorting to radiographic analysis or destructive bend testing, with considerable delay between the time the joint is made and the time the test results are obtained. All of the foregoing circumstances combine to increase the likelihood that a trainee will develop bad habits in the initial stages of learning, which habits are thereafter difficult to correct.
Accordingly, it is the object and purpose of the present invention to provide an electric arc welding simulator for use in the instruction of electric arc welding.
It is also an object of the present invention to provide a welding simulator that simulates the consumption of a welding rod.
It is another object of the present invention to provide a welding simulator with which a trainee can practice the advancing of a welding rod over a workpiece with a predetermined pattern of movement.
It is yet another object of the present invention to provide a welding simulator that cues the trainee in the event the trainee fails to hold the simulator at a predetermined orientation.